Spectroscopic study of some aromatic hydrazones derivated from aromatic substituted benzophenones and benzaldydes

Author(s): Anwar T.M.AL-Thib, Noor A.Khudhair

Four novel aromatic hydrazones not hydrolysed under ordinary conditions were synthesized in this research by condensation reactions between 2,4-dinitrophenylhydrazine: firstly with 2,4,4‘- trihydroxybenzophenone to give I, secondly with phydroxybenzophenone to give II, thirdly with pdimethylaminobenzaldhyde to give III and fourthly with paminobenzaldehyde to give IV. The molecular structures of these aromatic hydrazones obtained were characterized based on melting points, elemental analysis and UV-Visible spectra. The electronic absorption spectra of hydrazones obtained were studied in different solvents of ethanol, DMF ((CH3)2NCHO), water, chloroform, carbon tetrachloride and cyclohexane. The appeared absorption bands in ethanol solvent were attributed to corresponding electronic transitions, and discussed. The absorption bands at 291 to 411 nm obtained in electronic spectra of the synthesized new aromatic hydrazones were attributed to (ðï‚®ð*) transition which arise from substituted aromatic benzophenone or benzaldehyde rings and directed along of molecule in hydrazones. These transitions are supposed to represent the intramolecular charge-transfer (CT) complexes bands in which the substituted two halves of benzophenone and benzaldehyde rings are as charge donors and the substituted phenylhydrazine ring is the charge acceptor. Also, the effect of non-polar and polar solvents on the electronic spectra have measured and discussed. The physical-spectroscopic coefficients in molecular structural shapes of intra CT complexes molecules such as transition energies (ECT), molar extinction coefficients (CT),molecular oscillator strength (ƒCT), transition molecular dipole moment (µCT) and molecular resonance energy (ER) have been calculated and discussed.

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